1. Field of the Invention
The present invention relates to a lid made of a resin for a case for accommodating a solid-state imaging device, a method of manufacturing the same, and a solid-state imaging apparatus.
2. Related Background Art
In general, a solid-state imaging apparatus comprises a case for accommodating a solid-state imaging device, and a transparent lid which closes the case and transmits incident light therethrough. Examples of the lid include transparent resins, transparent glass, and transparent ceramics, among which the transparent resins are advantageously used in terms of the cost, easiness in molding, etc.
It has been conventionally known a resin molding technique by using a die. In the resin molding method, a resin before solidified is injected into an inside cavity of a die, and after cooling the resin in the die, the resin molded body is pulled out from the die. This pulling out step is referred to as “protrusion”. There are various methods for protrusion methods of the molded body, and typically a method by using an ejector pin has been known.
When injection-molding a resin in general, the resin is likely to flow into a gap between a die body and an ejector pin for taking the molded body out of the die, so that burrs are likely to occur in the part (ejector pin mark) ejected by the ejector pin.
FIG. 1 is a perspective view of a conventional lid 10.
Lid 10 has a lid upper surface 10a, a lid lower surface 10b and a side face part 50. A window area 60 (mirror-finished area) is formed in the center area of the lid 10. When ejecting a lid-forming part of a molded body with ejector pins at the time of injection-molding, ejector pin marks 44 are likely to remain on a surface 10a of the lid 10 in a conventional method as shown in FIG. 1, thereby generating burrs. These burrs may drop into a solid-state imaging apparatus during or after assembling the solid-state imaging apparatus, thereby causing defects in imaging.
While it has been proposed to cover a burr-generating portion with a sealant resin for burrs in a case used in a solid-state imaging apparatus (see Patent Document 1: Japanese Patent Application Laid-Open No. HEI 11-177074), for example, covering the ejector pin EP marks on the lid surface with a sealant resin makes the lid form irregular, and is inefficient in terms of cost as well.
It is an object of the present invention to provide a lid made of a resin for accommodating a solid-state imaging device, which leaves no ejector pin marks on a lid surface and is free of burrs when molding the lid made of a resin by injection molding.